The Omega Nebula in H-alpha light (M 17)

clic for 30% size 1154 x 790 (518 kB)

clic here for 50% size 2004 x 1336 (997 kB)

About this Image

At some 5,000 light years distant in the constellation of Sagittarius the beautiful emission Nebula M 17 is situated. The Omega Nebula M17, also called the Swan Nebula, the Horseshoe Nebula, or (especially on the southern hemisphere) the Lobster Nebula, is a region of star formation and shines by excited emission, caused by the higher energy radiation of young stars. Unlike in many other emission nebulae, however, these stars are not obvious in optical images, but hidden in the nebula. Star formation is either still active in this nebula, or ceased very recently. A small cluster of about 35 bright but obscurred stars seems to be imbedded in the nebulosity.

Compare multiwavelenght images here: 1.
Compare a close-up image from the HST: 2.
Compare an ESO image here: 3.

Below you see the center crop of the above image in 50/100% size showing the chaotic center of this nebula area.
North is down

clic for 100% size 1090 x 796 (194 kB)

Technical Details


TEC-140 APO refractor with TEC flattener at f/7

Mount AP-400 GEM
Camera SBIG STL-11000M at -25C, internal filter wheel
Filters Astronomik H-alpha,
Date May 22, 2006.
Location Hakos/Namibia
Sky Conditions mag 7, high transparency, temperature 15 C,
Exposure Ha = 140 minutes (10 min sub-exposures),
all 1x1.
Processing Image aquisition, in Maxim DL 4.11; calibration and preprocessing in CCD-Stack;
Photoshop: curves, mild unsharp mask;
wavelet processing for brighter nebula parts;